Various products on the market are provided with various decorations. Decorations may be formed by printing a decorative layer on products through ink-jet printing, screen printing, pad printing or the like. For example, some of fishing rods, a sort of products on the market, are provided with a decorative layer on the surface thereof through ink-jet printing so as to cover various user preferences or to stimulate user interest (see, e.g., Japanese Patent Application Publication No. 2008-206415 and Japanese Patent Application Publication No. H. 9-23789). Further, many techniques have been proposed for providing decoration on tubular products other than fishing rods by ink-jet printing (see, e.g., Japanese Patent Application Publication No. 2010-143200).
The ink-jet printing mentioned above is one of printing methods using printers, wherein liquid ink particles are discharged onto a printing substrate to draw dots that collectively represent characters and figures. However, there are some drawbacks when printing a decorative layer on a tubular body by ink-jet printing; and the drawbacks are specific to tubular bodies.
For instance, when a decorative layer is printed on a surface of a fishing rod, which is an example of the above-mentioned tubular structure, by ink-jet printing, more specifically, when a decorative layer is printed by ink-jet printing in several steps in the circumferential direction of the rod, circumferential borders (seams) between the divided decorative layers printed in the above steps may not be made continuously due to characteristics of an ink-jet printing machine or due to an axial tapering configuration of the fishing rod. In particular, at the border (seam) between the first divided decorative layer printed in the first circumferential step and the last divided decorative layer printed in the last circumferential step, the edges of these divided decorative layers may be largely separated or largely overlapped from/with each other in the circumferential direction due to the accumulation of small errors at each printing step. The separations or overlaps appear as streaky lines along the axial direction of the rod on the surface of the rod, which impairs the decorative appearance.
Not only in the ink-jet printing, such errors at the borders between the decorative layers may also happen in various printing methods such as screen printing and pad printing.